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Table 1 shows the statistics of Hydroxybutyrate (BHB) products’ review data collected on Amazon.com. The BHB product reviews in text were collected within 2 months of the year 2019. The entire text dataset include 30877 reviews, 105703 sentences, and 1574171 words. Those product reviews reflect the clients’ comments on 71 products under 26 brands.

Results

Word-level Sentiment Analysis

Word-level sentiment analysis utilizes lexicon to classify the words in the online reviews of one product into positive and negative categories. The process put all the recognized positive words and recognized negative words into two separate classes. Since the human language is abundant with the complicated expressions, the portions of positive and negative words are relatively small. We then viewed those numbers comparatively. Table 2 partially showcases the word-level sentiment analysis of β-Hydroxybutyrate (BHB) powder and capsule products. The flavors used in BHB powder products include lemon, lime, lemon lime, lemon strawberry, and lemon raspberry. Most of the flavored items were assigned with positive/negative ratios higher than the unflavored items. Only one lemon item had the positive/negative ratio 1.68. Three out of four capsule items received less than 2 or even lower positive/negative ratios. Such results suggest that appropriate flavoring improves the consumer acceptance of BHB products. Besides, word clouds were generated based on the online reviews of flavored/unflavored BHB products listed in Table 2.

Figure 2 displays the word clouds of lemon-series and unflavored BHB powder products #2, #3, #4, and #7 from Table 2. The word size in the word cloud is proportional to the frequency of that word occurring in the reviews. For instance, the word cloud of product #2 clearly shows that consumers care about the taste and ketosis functions of the BHB product (i.e., increasing body ketone). The big words such as “flavor” and “great” suggested that the consumers who used product #2 expressed highly-positive feedback on the flavoring part of the product. We then summarized the top-3 high-frequency words in the word clouds of analyzed BHB products in Table 3. High-frequency words such as “keto”, “taste”, “product”, “flavor”, and “great” can be found in the word clouds of products #2, #3, #4, and #7 (See Table 3). The patterns of top-3 high-frequency words were not identical from product to product, however, the same words such as “taste” occurred repeatedly in different orders of BHB products’ high-frequency word lists. From those highly-repeated words, we speculate that the product development team behind those products attempted to grab their consumers by making tasty functional drink mix. In the word cloud of product #7, we found the word “diarrhea” clearly on the corner indicating the occurrence of such side effect in body. Similar side effects caused by magnesium citrate over intake were found in clinics, and it worsened gastrointestinal load. It also illustrates that not everyone adapts to the BHB supplements, and appropriate daily intake (e.g., amount, dosage, and intake approach) should be recommended.

We then extracted the online reviews of the rest BHB capsule products (i.e., product #8, #9, #10, and #11) in Table 2, and generated their word clouds (See Figure 3). We saw different big or small words on each word cloud in Figure 3. “lost pounds”, “weight loss”, “lose”, “weight” can be observed in the word clouds of product #8, #9, and #11, respectively, which reflects the weight loss function of BHB as supplement. The word “appetite” in the word cloud of product #9 might be related to the appetite disturbance caused by BHB. Then, we captured the word “energy” in the word clouds of product #9, #10, and #11 suggesting the energy enhancer function of BHB. Plus, the words “help”, “great”, “will”, “work”, “helped”, and “happy” in the word clouds in Figure 3 give us confidence in the BHB’s supplement functions. Their corresponding high-frequency words pattern is straightforward. The words “keto”, “help”, “supplement”, “product” in the word clouds of product #8 to #11 appeared in different frequency orders (See Table 3). We can see that the massive consumers put emphasis upon BHB’s functions. Many of them reflect positive feedbacks on BHB’s functions, especially weight loss and energy enhancer.

Sentence-level sentiment analysis: Flavor and Price

Figure 4 shows the sentence-level sentiment analysis of BHB products’ online reviews with flavor focus, including bubble chart of BHB products (Figure 4A), compound scores of selected branded BHB products (Figure 4B), and average compound scores of flavored BHB products (Figure 4C). In Figure 4A, some of the BHB products have large circles while others have small ones. Large circles indicate that the product review polarities are higher and more customers gave positive feedbacks than those who gave negative feedbacks. Other small circles suggest the adverse direction.

Flavored Products: From Figure 4A, we can see that all sorts of flavors such as apple, berry, lemon, orange, and etc. have been used to diversify the β-Hydroxybutyrate (BHB) products’ taste profiles. Those different flavored BHB products are priced within a wide range, from $18 to $99. Creative flavor combinations such as lemon-lime, lemon-raspberry, and orange-mango were observed in Figure 4A. Those BHB products with combined flavors actually had higher compound scores than other flavored BHB products. For instance, some apple or caramel flavored BHB products had high compound scores, however, more BHB products with combined flavors had such high compound scores, and some among them had the highest compound scores. Those BHB products with combined flavor actually occupied a certain space in Figure 4A. We selected some of the representative BHB products and placed them together in Figure 4B. The compound scores of those flavored BHB powder products were high, more than 20%. Besides, we grouped all the flavored BHB products together in Figure 4C. From Figure 4C, we found that most of the flavor categories have average compound scores higher than 20%. Five flavor categories among them have average compound scores even higher than 25%, and three of them got average compound scores close to or higher than 30%. Those top products were flavored with apple, berry, cherry, lemonlime, and lemon-strawberry flavors, most of which fell in the category of the citrus flavors. It is not too surprising. Citrus flavors have been investigated for a long time [19]. This flavor category has been widely-accepted to people all over the world, more importantly, is available and tastes similar globally. Those flavors have clean, refreshing tasting note, and are well-compatible with many other flavors and ingredients. Thus, it is relatively easy to commercialize citrus flavor–involved products around the world. The feasibility of design, process, and production also makes the application of citrus flavors convenient [20,21]. Citrus flavors have succeeded in bringing crisp sensation to various beverages, snacks and confections. Products with citrus flavors under brands such as Tropicana, Gatorade, Hi Chew can be found everywhere. The high average compound scores of those BHB products flavored with citrus flavors aligned with the historical popularity of citrus flavors. It is worth mentioning that the combination of different citrus flavors such as orange-mango, lemon-raspberry, and so forth can lead to even higher polarity of their product feedbacks. Such creation makes the monotonous supplements stand out and differentiate the brand among competitors.

Unflavored Products: For unflavored BHB products, most prices overlapped with each other within a narrow range from $15 to $40 (See Figure 4A). The compound scores of unflavored BHB products had a broad range from -22% to 37% (See Figures 4A, 4B). The compound scores of BHB capsule products fluctuated heavily. Among them, quite a few BHB capsule products had the compound scores above 20%, while others had the compound scores below 5%. The other few unflavored BHB powders and liquid had the compound scores of 12.21% (powder), 15.06% (powder), and 13.94% (liquid). Those items were good products, but they were not as competitive as those with higher compound scores. Although the unflavored BHB products were sold at low prices, they were still less popular or competitive than others. For instance, flavored BHB products under the brand C and E clearly exhibited the compound scores higher than the other unflavored BHB products (See Figure 4B). More additives such as flavors and sweeteners increase the product price, however the high quality of the resultant products still drive consumers back to the products. Besides, those products’ compound scores were calculated based on the certain amounts of consumers’ reviews. The compound scores of the BHB products such as A Capsule 2 and B Powder Unflavored 1 from Figure 4B were generated based on 39 and 170 reviews, respectively. The less appealing compound scores of those unflavored powder/capsule products are based on the common agreement among consumers. The monotonous products cannot arouse consumers’ continuous shopping desire.

Sentence-level sentiment analysis: Dosage and Package

The current BHB market provides our consumers with different packages. The packages of 1 oz to 55 oz were used to bottle BHB products with different dosage forms. Figure 5 shows the sentencelevel sentiment analysis of BHB products’ online reviews with package focus.
All Dosage: Figure 5A shows the bubble chart of BHB products plotted with package versus dosage format. From Figure 5A, we observed 3 major dosage forms on the current market of BHB products, including powder, capsule, and liquid. For BHB capsule, their packaging sizes were either 4 oz or 5 oz bottle, close to 120 cc or 150 cc. That size fit most of the bottling capacity of capsule manufactures. The BHB capsule products received a wide range of compound scores, from -22% to 37%. The BHB capsule products have straightforward packaging and functions, hence, it is less obvious to explain the fluctuation of their compound scores. Nevertheless, when we zoomed into each review of BHB capsules with low compound scores, we found the reviews such as “Gives you a lot of energy but no weight loss”, “It did nothing and there was no information with it to tell me what I should do to make it work, sorry I was very disappointed.”, and “Did nothing at all. No change, not even a pound dropped combined with diet and exercise. Save your money.” among all the other positive reviews. The body metabolisms of BHB products still deserve further investigation. More clinic studies of BHB products are needed to address this issue. The consumers might also be subjective and with incorrect expectation to some extent. On the other hand, the supplement manufacturers should review those insufficient customers’ feedbacks and educate their clients with the appropriate use of their products. Unlike capsules, BHB powder products were commercialized with various packages shown in Figure 5A. There is no unified package size for the powder products. More creation becomes possible in bottling BHB powder products.

Powder Dosage: Figure 5B displays the average compound scores of BHB powder products in each package category. Most of the packages received the average compound scores higher than 20%. Among them, three packages such as 12 oz, 30 oz, and 42 oz bottles received the average compound scores higher than 30%. The average compound score of BHB powder products in 1 oz packet was also above 20%, suggesting that consumers should welcome the single-size samples prior to massive consumption. Some of those high polarity items such as BHB powder in 42 oz package did not have sufficient amount of online reviews. Unlike flavor factor, we did not observe exclusive impact of package upon consumption orientation, especially for BHB powder products. All package items have experienced both high and low compound scores. Package size is not a dominant factor in BHB product design. Other factors including formula, price, and label all play a role in the market performance of the BHB products.

Complex Analysis

The sentiment analysis provides us with the polarity information of the text data, while the complex analysis summarizes the word number, sentence number, and character number in the reviews of each BHB product. The combination of both analyses enables us to understand the robustness of the consumers’ feedbacks on BHB products. Table 4 lists the complex analysis of three brands’ BHB products. It is part of the 71 BHB products’ complex analyses. The three products under brand A received more than 300 reviews referring to over 1000 sentences, 14000 words, and 65000 characters. The consumers paid certain amount of attention to the BHB products under brand A. Interestingly, the products under brand A had very similar patterns of text complexity, which was also found in the products of brand C. Five out of six products under brand C had almost overlapping numeric values in # of reviews, # of sentences, # of words, and # of characters with small deviations. Similar text complexity is observed under one brand, while large differences appear among brands. We can see that brands help differentiating products among companies. Rational consumers are willing to trust products with higher reputation more than others. Those products with high reputation automatically form a marketing event for their brands.

To have a comprehensive understanding, we mapped the BHB products’ distributions under the confinement of sentiment and complexity analyses. As such, Figure 6 presents the mapping of BHB products labeled with flavors under the combined conditions of online reviews’ polarity and their complexity. In Figure. 6A and Figure 6B, the marks’ colors indicate different flavors, while the same or similar color suggests the same flavor or similar ones. Figure 6A shows the flavor impact on product reviews’ polarity in the context of the # of reviews. Data points scattered all over the plot in Figure 6A. For instance, we observed an unflavored BHB product with compound score -22% generated from 1 review, a lemon-lime BHB powder with compound score 55% from 3 reviews, and another lemon -lime BHB powder with compound score 23% from over 235 reviews. Products had very distinctive analytical results. For convenience, we divided the entire plot into 4 sections by using the boundary of compound% = 20 and # of Reviews or # of Sentences = 100. In Figure 6A, most of the unflavored BHB products were located in the center of the plot, while a certain amount of the unflavored BHB products sat in the left-down part of the figure, the low compound score and low # of Reviews region. On the contrary, quite a few flavored BHB products gathered in the right-top part, the high compound score and high # of Reviews region. Besides, almost all the flavored BHB products had the compound scores higher than 20%, nevertheless, there were more unflavored BHB products with compound scores < 20% than those with compound scores > 20%. Such observations fortified our previous observation that flavored BHB products were more easily accepted by the massive consumers.

It should be noticed that the compound score is assigned based on the entire pool of reviews for one product. We should then take the text statistics of those reviews into consideration. Unlike the lengthy text in books, most of the online reviews for one product involve less than 5 sentences, and only a few of them directly express sentiment. We utilized # of Sentences as substitute of # of Reviews for the same analysis. It gives us another angle to view the product polarity in the context of the alternative text statistics. Figure 6B shows the plot of compound score versus # of Sentences with flavor label. Compared with Figure 6A, Figure 6B with # of Sentences has similar range of text statistics. The data in Figure 6B overally shifted to the right side of higher order magnitude. It was because large portion of the BHB products’ reviews contained more than one sentence. Most of the flavored BHB products assembled in the right-top part of Figure 6B, the high compound score and high # of Reviews region. Many of the flavors in that region were combined citrus flavors such as lemon-lime, lemon-strawberry, lemonraspberry, and orange-mango. Other flavored BHB products were found outside of that region. For instance, chocolate, apple, and another lemon-lime BHB powder products received less than 10 either # of Reviews or # of Sentences. Those products were located in the left-top region. It is likely that they would receive more positive online reviews, and shift towards right-top region. Similar to Figure 6A, more unflavored BHB products with compound score < 20% was observed in Figure 6B. Meanwhile, the relative pointto- point distances of the unflavored BHB products were changed also due to the fact that many reviews contain more sentences than others.

Packaging is another dimension we previously mentioned in sentence-level sentiment analysis. We applied the same approach in mapping the BHB products’ distributions labeled with packages under the confinement of sentiment and complexity analyses (see Figure 7A and Figure 7B). The colors in Figure 7A and Figure 7B indicate different packages, especially volumes. Among all the packages, similar volumes such as 20 oz and 25 oz, 1 oz and 4 oz share the same blue and voilet in Figure 7, respectively. Figure 7A displays the BHB products’ distribution labeled with packages under the combined conditions of compound score and # of Reviews. Large volume packages appeared on the right-top side of the plot. Those BHB products’ bottles had volumes from 20 oz to 55 oz. Those items overlapped with the flavored BHB products with compound scores > 20% in Figure 6A. The majority of the flavored BHB powder products have package volumes higher than those of unflavored BHB products. Higher volume such as 55 oz can not only load more servings in one bottle but also introduce more marketing and educational information, which makes the product look more appealing. Some items packed in 1 oz packages had compound score > 20% while other items bottled in 4 oz volume had compound score <20%. Those 1 oz items were all flavored BHB products inserted in 1 serving packages. It demonstrates that consumers are willing to accepting test samples of flavored BHB products. Their feedbacks, especially positive ones, are independent on package volume. With the experience of test samples, customers will likely give more positive comments to their full-size items. Figure 7B shows the BHB products’ distribution labeled with packages under the combined conditions of compound score and # of Sentences. Likewise, the BHB products’ distribution in Figure 7B is similar to that in Figure 7A. The only difference lies in the relative positions of each data point as mentioned before.

Discussion

This piece of research conducted sentiment analysis of BHB products’ online reviews to understand how the current BHB products be accepted by the massive consumers. Two factors including flavors and packages were taken into consideration during analysis. In terms of flavors, they are not only edible ingredients but also multisensory phenomena with the integration of taste, olfactory, and other sensory information into a perceived property of the product rather than a collection of individual sensory attributes. For clients, the sensory pleasure is their motivation to consume a product and experience the flavoring journey again and again [22]. The sensory qualities from flavors reduce the product risk and increase its consumer affinity. When we consume supplements, especially sensory products, flavors become more important than the sum of other parts. In fact, flavor can be regarded as a primary factor in driving consumption behavior [23]. It was demonstrated that liking with flavored products increases chewing and swallowing rates [24]. In the current research, we observed that flavored BHB products were more popular than unflavored BHB products. The popularity of flavored BHB products is independent on the package volume. Among the flavored BHB products, the products with the combined citrus flavors such as lemon-raspberry can further increase the polarity of their online reviews. In other words, those particular flavored BHB products stand out among competitors.

Package is another factor when we conducted sentiment analysis of BHB products. It is the first visualization of product to the consumers. It asserts a critical role in product marketing and sales. Research shows that even the position of an image on the packaging affects consumers’ perception of the product weight and package evaluation [25]. A considerable amount of investigations on multisensory product perception suggest that packaging features can bias consumers’ flavor evaluations [26]. Another consumer research shows that altering packaging materials affect not only sustainability perceptions but also several other aspects including perceived taste and quality [27]. Our observation indicates that the packages of the flavored BHB products are distinct from those of the unflavored BHB products, especially packaging size. For the most of unflavored BHB products, their packaging sizes are limited in design. Compared with those unflavored BHB products, flavored BHB products have a wider range of package volumes which offers more possibilities for product marketing and education. In addition to the major labels of flavor and package, the sentiment analysis enables us to notice the fact that massive consumers emphasize on the BHB’s functions such as weight loss and energy enhancer. Consumers are not willing to seeing that products lose those functions and work only as placebos. Some side effects of BHB products such as diarrhea suggest that we should continue more clinical studies and user education. From the complex analysis, brand implicitly deploys product differentiation and credit enhancement on this emerging market. The product differentiation refers to the business strategy of highlighting the unique features and benefits to separate it from competitors. When it functions, brand can create additional intangible value, consumer loyalty, and even market trend.

Conclusion

Sentiment analysis of β-Hydroxybutyrate (BHB) products’ online consumer reviews was carried out to explore consumer insights on the emerging marketing of dietary supplements. Our observations demonstrate that flavoring plays a key role in the BHB product market together with other factors such as packaging and brand. Flavored BHB products are more popular than unflavored BHB products, and they are more acceptable by massive consumers despite of their high prices. Creative flavors such as lemonraspberry enable BHB products to stand out among competitors. High volume packaging provides consumers with more possibilities of marketing and education. Meanwhile, we cannot ignore other factors such as active functions and brand building.

Acknowledgement

I would like to thank my parents for their endless love and support all the time, and sincerely hope that the technological innovation improves their life quality and other elders’.

Funding

This research was made possible with funding from Nutraceutical Corporation.

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