Tea Plant

Ali Shields et al. (2023) · JAMA dermatology

Many people with acne turn to over-the-counter vitamins, minerals, herbal extracts, and probiotics hoping for a gentler alternative to prescription treatments -- but how well do these actually work? This systematic review pooled 42 randomized trials (3,346 participants total) testing oral nutraceuticals for acne, following a pre-registered research protocol and searching four major databases through January 2023. The interventions ranged from zinc and vitamins to green tea extract, fenugreek, probiotics, fish oil, and a traditional Korean herbal formula, giving a rare side-by-side look at how these popular supplements stack up against placebo. Reviewers independently screened thousands of records down to 42 qualifying randomized trials and rated each one's quality using a standard bias-assessment tool. Most trials (27 of 42) were rated poor quality, 11 fair, and only 4 good -- a reminder that supplement research overall is thinner than for prescription acne treatments. Outcomes tracked included clinician-rated improvement, lesion counts, patient-reported satisfaction, and side effects. Results varied widely by supplement. Zinc, the most-studied option, worked in only about half its trials and caused the most stomach-related side effects of anything tested, though higher doses (600 mg/day) tended to work better than lower ones. Vitamin D (1,000 IU/day) meaningfully reduced inflamed acne lesions in people who were vitamin D-deficient. Green tea extract cut inflammatory lesion counts but did not improve people's reported quality of life. Probiotics -- especially certain Lactobacillus strains -- showed the most consistently positive results across several small trials and were well tolerated. Omega-3 and omega-6 fatty acids reduced both inflamed and non-inflamed lesions after about 10 weeks. Pantothenic acid (vitamin B5) helped, but only at a dose far above typical nutritional intake. Fenugreek seed extract underperformed compared with an antibiotic in one small study. Four options -- vitamin D, green tea extract, probiotics, and the herbal formula cheongsangbangpoong-tang -- had the strongest (though still limited) supporting evidence. Vitamin D and omega-3/6 fatty acids carried the lowest risk in these trials, since their effective doses are close to normal nutritional intake, while zinc showed mixed results and a higher side-effect rate. Overall, most of this evidence comes from small, lower-quality trials; none of these supplements was tested as a replacement for proven acne treatments — the trials studied them as possible add-ons.

Zhiyong Long et al. (2023) · Frontiers in immunology

Whether the plant compounds often discussed for rheumatoid arthritis — turmeric, green tea, pomegranate, garlic — actually do anything is the question this meta-analysis set out to answer. This review gathered every randomized trial it could find on the question: 47 trials, nearly 3,900 people, fifteen different plant polyphenols, from Iran, China, Korea, Egypt, Japan, Brazil, India and the United States. The clearest picture came from two of them. The first is total glucosides of paeony, an extract of Chinese peony root that is a licensed prescription medicine in China. Twenty-three trials tested it — always added to standard RA drugs like methotrexate, never instead of them. Disease activity scores came down, and so did CRP, ESR and rheumatoid factor, the blood markers doctors track. The most interesting result: people taking it reported *fewer* side effects than people on the standard drugs alone. That fits how it is used clinically — it appears to soften the toll the conventional drugs take on the liver and stomach. The second is curcumin, the yellow compound in turmeric. Five trials, and the same direction: lower disease activity, lower inflammatory markers, no extra side effects. Green tea polyphenols looked promising across two trials. Saffron did not show a clear effect. Everything else — pomegranate, garlic, resveratrol, sesame, cinnamon, ginger, kudzu, cranberry, olive oil, quercetin — rests on one or two small trials apiece, which is encouraging but not yet evidence that bears weight. The honest caveat, which the authors state plainly themselves: the trials disagreed with each other a great deal, most were small, and when the researchers sliced the data by dose and duration some of the headline benefits faded. Nearly all of these were add-on studies. Nobody tested a polyphenol against methotrexate, so the evidence says nothing about replacing a prescribed medication. What it does support is turmeric and peony extract as the best-evidenced candidates, studied as additions to existing treatment rather than replacements for it.

Ziqing Soh et al. (2025) · Journal of food and drug analysis

This double-blind, randomized, placebo-controlled trial with 30 young Malaysian women explored whether a beverage combining chamomile and l-theanine could ease primary dysmenorrhea - menstrual cramping that occurs without any underlying pelvic disease. Chamomile (Matricaria recutita) is a flowering herb long used as a calming remedy; the study intervention used a standardized flower extract of it. L-theanine is a non-protein amino acid concentrated in tea leaves (Camellia sinensis), used in supplements to support relaxation. The trial paired both in a functional beverage (CTT) and tested it against a chamomile-flavored placebo (non-CTT) to see whether the combination eased pain, mood, and sleep during menstruation. Thirty women aged 18-30 with primary dysmenorrhea (pain rated at least 4 of 10 on a visual scale across three cycles) were randomly split into a CTT group (480 mg chamomile extract plus 200 mg l-theanine daily) or a non-CTT control group, drinking two 240 mL packs daily - one on waking, one before bed - for five days spanning two days before their period through its third day. Pain was tracked with two 0-10 scales, symptoms with the 18-item Cox Menstrual Symptom Scale, sleep with the Pittsburgh Sleep Quality Index, and mood with the Profile of Mood States. Compared to their own baseline, women drinking CTT saw pain scores drop by roughly 57% on both pain scales (p<0.001), a large reduction over five days. Eight menstrual symptoms also eased significantly, including lower abdominal pain (down 53%), back pain (down 56%), and irritability (down 45%, all p<0.05). Mood shifted too: depression scores fell 12% and vigor (energy and alertness) rose 62% (p<0.05). On sleep, only "daytime dysfunction" - grogginess, poor concentration, and low energy during the day - improved (down 32%, p<0.05); overall sleep quality, how long it took to fall asleep, and total sleep time did not change significantly. Hemoglobin levels, checked with a finger-prick test, were unaffected in either group, likely because red blood cells take weeks to months to regenerate, too slow to show up in five days. Interestingly, the placebo group also felt calmer on a few measures, which the researchers link to the shared chamomile scent and flavor rather than to any active ingredient. For young women managing primary dysmenorrhea without relying on NSAIDs, a short course of this chamomile-l-theanine beverage appears to meaningfully ease pain and several physical and emotional symptoms, with no reported side effects. Because chamomile and l-theanine were only tested together, it is not yet clear how much each contributes individually, and the tiny sample (15 per group) and single five-day cycle mean the results are preliminary. Longer trials spanning multiple cycles, larger and more diverse groups, and a scent-neutral placebo are needed before firmer conclusions can be drawn.