Nature,
understood.

FOR KNOWLEDGE • NOT MEDICAL ADVICE

The plant and its compounds

Açaí is the dark-purple fruit of Euterpe oleracea, a palm associated with the Brazilian Amazon. Its pigments include anthocyanins, a group of plant polyphenols investigated for antioxidant activity. [1]

How might it affect our body?

Researchers measure how açaí consumption affects the body’s antioxidant defences and blood-vessel function. Oxidative stress describes an imbalance between reactive molecules and the systems that keep them in check. A change in a laboratory marker is useful scientific information, but it does not establish that a food prevents disease. [2] [3]

Diseases and conditions studied

• Cardiovascular disease risk: a controlled crossover study in 23 otherwise healthy men with overweight found short-term improvements in how an arm artery widened after an açaí meal. This measured vascular function, not heart attacks or long-term heart-disease prevention. [2]
• Cholesterol and metabolic health: a four-week crossover study in 30 healthy adults reported increases in HDL cholesterol and some antioxidant markers relative to baseline. It compared açaí with juçara juice and found no significant differences between the juices; it cannot establish treatment of high cholesterol or diabetes. [3]
• Obesity: reliable evidence does not establish açaí as a weight-loss treatment. [1]

Safety context

Raw juice can carry infection risks. Açaí products may affect blood glucose or interfere with some gastrointestinal MRI results. Discuss supplement use with a healthcare professional if you take medicines. [1]

Scientific evidence & sources

1. NCCIH: Açaí — usefulness and safetyNIH evidence overview; limitations and safety.
2. Alqurashi et al. (2016), American Journal of Clinical NutritionRandomised crossover trial: açaí meal and vascular function; 23 men.
3. de Liz et al. (2020), Clinical NutritionFour-week randomised crossover study: cholesterol and antioxidant markers; 30 adults.

FOR KNOWLEDGE • NOT MEDICAL ADVICE

One leaf, different preparations

Aloe’s inner-leaf gel, yellow latex and whole-leaf extracts have different chemical compositions and risks. A skin gel cannot be treated as equivalent to a drink or supplement. [1]

How might it affect our body?

Skin repair involves rebuilding tissue and regulating inflammation. Aloe gel has been investigated for effects on these processes and for reducing pain and itching during burn healing. Proposed anti-inflammatory mechanisms help explain why researchers study it, but the clinical result depends on the preparation and the condition. [2]

Diseases and conditions studied

• Burn injuries: a small hospital trial compared aloe dressings with silver sulfadiazine on matched burns. Healing progressed faster and pain was lower with aloe; both sets of wounds healed within two weeks. This was supervised clinical care, not a test of applying a fresh leaf at home. [2]
• Acne vulgaris: an eight-week trial in 60 people found that aloe gel added to tretinoin reduced acne lesions more than tretinoin with a vehicle gel. The result supports studying an add-on treatment, not claiming aloe alone cures acne. [3]
• Psoriasis and type 2 diabetes: small studies suggest possible effects on skin symptoms or blood-glucose measures, respectively. Evidence remains limited, and oral products have distinct safety concerns. [1]
• Eczema, diabetic foot ulcers and ulcerative colitis: reliable evidence is insufficient to establish a benefit. [1]

Safety context

Skin irritation or allergy can occur. Oral latex can cause cramps and diarrhoea; oral leaf extracts have been associated with liver injury. Oral use may be unsafe during pregnancy or breastfeeding and can interact with medicines. [1]

Scientific evidence & sources

1. NCCIH: Aloe vera — usefulness and safetyNIH overview of topical and oral evidence.
2. Mahboub et al. (2022), Journal of Caring SciencesRandomised clinical trial: burn healing, itching and pain. Full text.
3. Hajheydari et al. (2014), Journal of Dermatological TreatmentRandomised trial: aloe plus tretinoin for mild-to-moderate acne; 60 participants.

FOR KNOWLEDGE • NOT MEDICAL ADVICE

The plant and its compounds

Withania somnifera is an evergreen shrub with a history in Ayurvedic medicine. Root and leaf extracts contain different mixtures of plant chemicals, including withanolides. These are proposed contributors to biological activity; other compounds may also be involved. [1]

How might it affect our body?

Researchers study perceived stress, sleep and cortisol, a hormone involved in the stress response. A 60-day trial in 54 adults with mild-to-moderate stress and anxiety reported lower symptom scores and morning salivary cortisol with a standardised root extract. The tested product also contained piperine, so it does not establish the same effect for every ashwagandha product. A hormone change alone does not demonstrate that the body has been “balanced”. [2]

Diseases and conditions studied

• Insomnia: an eight-week randomised trial in 80 adults, half with insomnia, found improvements in sleep measures with a specific root extract. Benefits were more apparent in the insomnia group. It was a small, short study. [3]
• Stress and anxiety symptoms: some trials suggest benefit, but everyday stress is not itself a disease. Results in stressed volunteers cannot automatically be applied to a diagnosed anxiety disorder. [1] [2]
• Generalised anxiety disorder: research is emerging. NIH describes a provisional specialist recommendation while emphasising that stronger evidence is needed. This is not a replacement for established care. [1]

Safety context

Possible effects include drowsiness and digestive upset; liver injury has also been reported. Thyroid effects and medicine interactions matter. Avoid during pregnancy and breastfeeding. Long-term safety is uncertain. [1]

Scientific evidence & sources

1. NIH Office of Dietary Supplements: AshwagandhaHealth-professional fact sheet: stress, anxiety, sleep and safety.
2. Majeed et al. (2023), MedicineRandomised placebo-controlled trial: stress, anxiety and hormone measures. Full text.
3. Langade et al. (2021), Journal of EthnopharmacologyRandomised placebo-controlled study: sleep in healthy adults and people with insomnia; 80 participants.

FOR KNOWLEDGE • NOT MEDICAL ADVICE

What is agnus castus?

Vitex agnus-castus, also called chasteberry or chaste tree, is native to the Mediterranean region and Central Asia. Research focuses on preparations of its fruit. The flowering plant pictured above helps identify the species; flowers are not the preparation tested in the PMS trial below. [1] [2]

How might it affect our body?

Its mechanism is not fully understood. Laboratory research suggests effects on the hypothalamus and pituitary, which help regulate hormones, potentially reducing release of prolactin. Prolactin may have a role in premenstrual symptoms. This is a proposed explanation, not proof that agnus castus broadly “balances hormones” or corrects a hormone disorder. [3]

Conditions and symptoms studied

• Premenstrual syndrome (PMS): a randomised, double-blind trial evaluated 170 women over three menstrual cycles. With a specific dry fruit extract, Ze 440, 52% achieved at least a 50% reduction in their overall symptom score, compared with 24% taking placebo. Symptoms assessed included irritability, mood changes, headache and breast fullness. This supports possible symptom relief, but does not establish a cure or the same benefit for every product. [2]
• Cycle-related breast pain or tenderness: studies suggest possible benefit, but NCCIH rates much of the PMS research as low to moderate quality and calls for stronger evidence. [1]
• Infertility and menopausal symptoms: reliable evidence for infertility is insufficient; menopause findings are preliminary. These uses should not be presented as established benefits. [1]

Safety context

Reported side effects include digestive upset, headache and itching. Pregnancy, breastfeeding and hormone-sensitive conditions, including some breast, uterine and ovarian cancers, require particular caution. [1] EMA advises medical review for people with pituitary disorders and warns that symptoms of prolactin-secreting tumours may be masked. Interactions with dopamine-related medicines, oestrogens and antioestrogens cannot be ruled out; discuss use with a doctor or pharmacist. [4]

Scientific evidence & sources

1. NCCIH: Chasteberry — usefulness and safetyNIH evidence overview: PMS, other uses and safety limitations.
2. Schellenberg (2001), BMJ — placebo-controlled PMS trialOriginal randomised study: 170 women, three menstrual cycles, Ze 440 fruit extract.
3. European Medicines Agency: Agnus castus fruitRegulatory overview: preparations, proposed mechanism and evidence assessment.
4. EMA: European Union herbal monograph, revision 1 (PDF)Professional safety guidance, interactions and pituitary-related precautions; EMA/HMPC/606742/2017.

Agnus castus sources checked 5 October 2026.

FOR KNOWLEDGE • NOT MEDICAL ADVICE

Where does it come from?

African prune, Prunus africana, is also known by the older scientific name Pygeum africanum. It grows mainly in tropical mountain habitats, with a native range spanning parts of mainland Africa, Comoros and Madagascar. [1] The material studied for urinary health is an extract of the dried trunk bark, not an ordinary dried prune fruit. [2]

What is in the bark?

The bark contains plant sterols such as beta-sitosterol, triterpenic acids including ursolic and oleanolic acid derivatives, fatty acids and ferulic-acid esters. Extraction changes which substances are concentrated, so raw bark and different commercial extracts cannot be assumed to have the same effects. [2]

How might it affect our body?

Researchers investigate effects on inflammatory signalling. A 2024 laboratory study exposed human immune cells to an inflammatory stimulus and tested a standardised bark extract for effects on cytokines, chemical messengers involved in inflammation. This work explores a possible mechanism; cells in a dish do not establish that taking a supplement improves symptoms or prevents disease. [3]

Conditions and symptoms studied

• Benign prostatic hyperplasia (BPH): this means non-cancerous enlargement of the prostate. It can press on the urethra and cause a weak stream, incomplete emptying and frequent urination, including at night. [6] A 1990 double-blind, placebo-controlled study of 263 patients over 60 days reported improvements in urinary measures with a particular pygeum extract. It is an older, short trial and does not establish long-term protection or equivalence to current medicines. [4]
• Daily-life relevance: urinary comfort and fewer interruptions are the practical outcomes of interest. Whether an individual benefits remains uncertain; the evidence does not justify promising better sleep or relief from every product.
• Disease prevention: the urinary-symptom trial did not test prevention of BPH or prostate cancer. Its results should not be used to make those claims. [4]

Safety context

EMA lists rare digestive effects, including nausea, constipation and diarrhoea. Do not use a product if allergic to its ingredients; discuss supplement use with a doctor or pharmacist. [5] New or worsening urinary symptoms need assessment. Blood in urine, pain when passing urine or inability to urinate require urgent medical help, such as an urgent GP appointment or NHS 111. [6]

Scientific evidence & sources

1. Royal Botanic Gardens, Kew: Prunus africanaAccepted species name, synonyms, habitat and native distribution.
2. EMA: Assessment report on Prunus africana bark (PDF)Plant material, chemical constituents and clinical assessment; EMA/HMPC/680624/2013.
3. Villar et al. (2024), International Journal of Molecular SciencesOriginal laboratory study of cytokine release in human immune cells; not a clinical trial.
4. Barlet et al. (1990), Wiener klinische WochenschriftOriginal placebo-controlled study of urinary symptoms: 263 patients, 60 days.
5. EMA: European Union herbal monograph (PDF)Traditional-use status, precautions and adverse effects; EMA/HMPC/680626/2013.
6. NHS: Enlarged prostateSymptoms, diagnosis and when to seek medical help.

African prune sources checked 5 October 2026.