Gelatin, the main ingredient in Jello, may modestly improve hair thickness, though it won’t speed up how fast your hair grows. The evidence is limited but interesting: in two studies, people who took 14 grams of gelatin daily saw their hair diameter increase by roughly 9 to 11 percent on average. That’s a noticeable difference in how thick each strand feels, but it’s not the same as regrowing lost hair or making hair grow longer faster.
What the Research Actually Shows
The most cited research on gelatin and hair comes from studies published in Nutrition Reports International. Participants who supplemented their normal diet with 14 grams of gelatin per day (about one tablespoon of unflavored gelatin powder) experienced an average increase in individual hair strand diameter of 9.3% in the first study and 11.3% in the second. Around 70% of participants in both studies saw their hair get thicker, with individual increases ranging from 5% to 45%.
The effect was strongest in people who started with thinner hair. People whose strands were already thick saw smaller changes. Importantly, the hair thickened because each strand got physically wider, not because the internal structure of the hair changed. Researchers confirmed this by measuring the mechanical strength of the fibers.
There’s a catch: within six months of stopping gelatin supplementation, hair diameter went back to its original level. The benefit only lasted as long as the supplementation continued.
Gelatin, Collagen, and How They’re Connected
Gelatin is essentially cooked collagen. Manufacturers produce collagen supplements by taking collagen-rich animal tissues like skin, bones, and fish scales, then breaking them down into gelatin that gets turned into powders, gummies, or capsules. So when you eat Jello or take a collagen supplement, you’re consuming closely related proteins.
Your hair follicles rely on collagen for structural support. The theory behind gelatin supplements is that animal collagen is similar enough to human collagen to provide useful building blocks. However, as Cleveland Clinic dermatologist Dr. Shilpi Khetarpal has noted, we don’t actually know whether ingested animal collagen translates into collagen production in human tissues. Your digestive system breaks gelatin down into amino acids before absorbing it, so there’s no guarantee those amino acids end up supporting your hair specifically.
Can a Cup of Jello Do the Job?
A standard serving of prepared Jello contains far less gelatin than the amounts used in research. The studies showing hair benefits used 14 grams of pure gelatin daily. A typical box of Jello dessert contains around 8 to 10 grams of gelatin total, split across four servings. You’d need to eat multiple servings per day to approach the studied dose, and flavored Jello also comes loaded with sugar or artificial sweeteners.
Unflavored gelatin powder is a more practical option if you want to try this. One packet (about 7 grams) dissolved in juice or a smoothie twice a day would get you to roughly 14 grams. This is a much more realistic approach than relying on dessert cups.
Gelatin Combined With Other Nutrients
A separate clinical study tested gelatin alongside vitamin A and an amino acid called L-cystine in people with diffuse hair loss (thinning spread across the entire scalp rather than in patches). Participants took 7,000 mg of gelatin daily along with the other two ingredients. The results were significant: the proportion of hair in the active growth phase increased, hair density improved by nearly 7%, and the number of damaged growing hairs dropped substantially compared to the placebo group, where hair quality actually continued to decline.
This suggests gelatin may work better as part of a combination rather than on its own. L-cystine is a sulfur-containing amino acid that contributes to keratin, the protein hair is made of, and vitamin A plays a role in cell growth. The gelatin in that study served as a protein base supplying additional amino acids like proline and glycine that support collagen production.
How Gelatin Compares to Biotin
Biotin (vitamin B7) is the supplement most commonly associated with hair growth, and for good reason. Research supports biotin more directly for promoting actual hair growth, particularly in people whose levels are low. Gelatin and collagen, by contrast, appear better suited for improving hair strength and thickness rather than stimulating new growth.
If your main concern is hair thinning or shedding, biotin has stronger evidence behind it. If you’re looking to make existing hair feel thicker and more resilient, gelatin supplementation has some support. The two aren’t mutually exclusive, and some people take both.
What to Realistically Expect
Gelatin isn’t a cure for hair loss. It won’t reverse pattern baldness or regrow hair in areas where follicles have already shut down. What it may do, based on the available research, is make individual strands slightly thicker and mechanically stronger. For someone with fine or thinning hair, that can translate into hair that looks and feels fuller.
Results in the studies took weeks to become measurable, and the benefits disappeared within six months of stopping. If you’re dealing with significant hair loss, the cause is more likely hormonal, genetic, or nutritional in a way that gelatin alone won’t address. But as a low-risk, inexpensive addition to your routine, 14 grams of unflavored gelatin per day has at least some evidence behind it for improving what’s already growing on your head.