It’s been used medicinally for thousands of years. Now it’s all over social media — for reasons that range from well-supported to wildly overstated. Here’s what the research actually says.
What is it?
Mastic is a resin harvested from the Pistacia lentiscus tree, native to the Greek island of Chios. For millennia it was used to settle stomachs, freshen breath, and treat infections. Modern science has started catching up — there’s now a reasonable body of research on its anti-inflammatory and antioxidant properties, with studies looking at everything from gut health to cardiovascular disease. MDPI
Where the evidence is solid
Gut health and H. pylori
This is where mastic gum has the most convincing support. Research published in the New England Journal of Medicine found it active against Helicobacter pylori — the bacteria that infects a majority of the global population and is linked to gastric ulcers and stomach cancer. Even very low doses (1 mg per day for two weeks) have been shown to help heal peptic ulcers.
New England Journal of Medicine
Heartburn and indigestion
In a randomised trial of 148 people with functional dyspepsia, a dose of 350 mg three times daily produced noticeable symptom improvements within three weeks. That’s a properly sized trial, not just anecdote. Greco Gum
Oral health
A 2023 review of 14 studies found evidence that chewing mastic resin can inhibit plaque accumulation — and reported no side effects or toxicity. Separately, mastic extract outperformed hydrogen peroxide at inhibiting the harmful bacteria associated with periodontal disease. The researchers note more work is needed, but the signal is there. Medical News Today
Anti-inflammatory and antioxidant effects
Multiple lab and clinical studies point to meaningful antioxidant, anti-inflammatory, and antimicrobial activity. No studies claim it can cure conditions outright, but the underlying mechanism is real. Medical news today
Cardiometabolic health
A 2024 narrative review found accumulating evidence from clinical trials and lab studies on mastic gum’s effects on lipid and glucose metabolism, cardiovascular and liver health, inflammation, body composition, and gut microbiota. Promising — but still developing. More trials are needed before drawing firm conclusions. PubMed Central
The jawline claim — honest assessment
This is the one that’s gone viral, so it deserves a careful look — because the honest answer is more nuanced than what you’ll see on social media.
The physiological logic makes sense on paper. Mastic gum is significantly harder than regular gum, which means chewing it provides a real workout for the masseter and temporalis muscles along the sides of the jaw. With consistent effort — think 15 to 30 minutes a session, a few times a day — there’s a reasonable case that those muscles can strengthen and grow over time, which could lend some squareness or firmness to the lower face.
There’s also the principle of Wolff’s Law: repeated mechanical loading on bone can stimulate mild remodelling and help maintain density. This is a recognised mechanism, though applied specifically to the jaw via chewing, the effect is subtle and not well-studied directly.
Where it gets complicated is the actual evidence. A 2024 study found that gum chewing training can strengthen the muscles involved in mastication — but the researchers found it did not alter facial shape or appearance. Orthodontists are consistent on this point: the sharp, defined jawline most people want comes primarily from low body fat and underlying bone structure, not from bigger jaw muscles. Chewing gum makes muscles bigger. Bigger muscles on the sides of the jaw can mean a wider face, not necessarily a more defined one. ScienceInsights
Any improvements will be gradual, modest, and highly individual — dependent on genetics, body fat levels, consistency, and starting muscle mass. It will not dramatically reshape bone structure or target facial fat. Approaching it as one small supportive tool, rather than a transformation strategy, is the right frame.
Practical notes and cautions
If you try mastic gum for the chewing benefits, start gradually rather than going straight into long daily sessions. The temporomandibular joint (TMJ) takes the load, and overuse can lead to jaw pain, headaches, clicking joints, or full TMJ disorders. Because mastic is hard, it can also encourage clenching or grinding, stress the joint unevenly if chewed on one side, and potentially damage fillings or crowns. People with allergies to other Pistacia plants should be cautious. Long-term safety data simply doesn’t exist yet. Toowoomba Dental
Anyone with a history of TMJ issues, significant dental work, or osteoporosis should check with a dentist or GP before starting.
| The short version: Mastic gum has genuinely good evidence behind it for gut health — particularly H. pylori and heartburn — and reasonable support for oral health and anti-inflammatory effects. The jawline claims are physiologically plausible but not well-proven, and merit realistic expectations. The risks are real if you overdo it, and scientists don’t yet know if it’s safe long-term. Worth knowing about; worth approaching with clear eyes. |
References:
https://www.mdpi.com/2072-6643/16/17/2941
https://www.mdpi.com/2072-6643/16/17/2941
https://www.nejm.org/doi/full/10.1056/NEJM199812243392618
https://www.medicalnewstoday.com/articles/mastic-gum
https://www.medicalnewstoday.com/articles/does-chewing-gum-help-jawline
https://scienceinsights.org/does-gum-make-your-jawline-better-facts-and-risks/
https://scienceinsights.org/does-gum-make-your-jawline-better-facts-and-risks/
https://www.toowoombadental.com.au/post/mastic-gum-risks
https://nutri.it.com/what-are-the-side-effects-of-mastic-gum-a-comprehensive-guide-for-informed-use