Table 2.

Key information on the 25 best‐selling herbal dietary supplements in the US mainstream multi‐outlet channel in 2015

Rank	Common/Latin Name	Retail sales a	% Changes 2014	Part of the plant generally used	Key constituent(s)	Condition frequently treated	Clinical efficacyb (Authors conclusions, reference)
1	Horehoundc Marrubium vulgare	114,9	8.5	Leaves and flowering tops	Diterpenes (e.g. marrubiin; flavonoids)	Catarrh associated with cooling; Dyspepsia symptoms such as swelling or flatulence	No systematic review/meta‐analyses available
2	Cranberry Vaccinium macrocarpon	65,7	16.0	Fruits	Proanthocyanidins	Urinary tract infection (prevention)	‘Given the large number of dropouts/withdrawals from studies (mainly attributed to the acceptability of consuming cranberry products particularly juice, over long periods), and the evidence that the benefit for preventing UTI is small, cranberry juice cannot currently be recommended for the prevention of UTIs’ (Jepson et al., 2012)
3	Echinacea Echinacea spp	60.1	7.4	Roots, aerial parts	Alkylamides, polysaccharides, caffeic acid derivatives	Common cold (immunostimulant)	‘Echinacea products have not here been shown to provide benefits for treating colds, although, it is possible there is a weak benefit from some Echinacea products: the results of individual prophylaxis trials consistently show positive (if non‐significant) trends, although potential effects are of questionable clinical relevance’ (Karsch Völk et al., 2014)
4	Garcinia Garcinia cambogia	54.8	−23.3	Pericarp of the fruit	Hydroxycitric acid	Weight loss	‘Garcinia extracts can cause short‐term weight loss. The magnitude of the effect is small, and the clinical relevance is uncertain’ (Onakpoya et al., 2011a)
5	Green tea Camellia sinensis	48.9	−23.4	Leaves	Caffeine, polyphenols (e.g. epigallocatechin and epigallocatechin‐3‐gallate)	Prevention of cardiovascular diseases and cancer; weight loss	Cardiovascular ‘The limited evidence suggests that tea has favourable effects on cardiovascular risk factors, but due to the small number of trials contributing to each analysis the results should be treated with some caution’ (Hartley et al., 2013). Cancer ‘There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention (Boehm et al., 2009)’. Weight loss ‘Green tea preparations appear to induce a small, statistically non‐significant weight loss in overweight or obese adults’ (Jurgens, 2012)
6	Black cohosh Cimicifuga racemosa	42.9	−5.1	Rhizome	Triterpenes (e.g. actein, cimicifugoside, 27‐deoxyactein)	Menopausal symptoms	‘There is currently insufficient evidence to support the use of black cohosh for menopausal symptoms’ (Leach and Moore, 2012).
7	Flax seed/oil Linum usitatissimum	36.3	−1.4	Seeds	α‐Linolenic acid, lignans, fibre,	Improvement of cardiovascular health	‘The present meta‐analysis suggests that consumption of flaxseed may lower blood pressure slightly. The beneficial potential of flaxseed to reduce blood pressure (especially diastolic blood pressure) may be greater when it is consumed as a whole seed and for a duration of >12 wk’ (Khalesi et al., 2015).
8	Ginger Zingiber officinale	25.6	21.8	Rhizome	Gingerols	Prevention of nausea and vomiting	‘For mild symptoms of nausea and emesis of pregnancy, ginger…..is associated with greater benefit than placebo’ (McParlin et al., 2016).
9	Valerian Valeriana officinalis	25.3	4.0	Roots	Iridoids, valepotriates, sesquiterpenes	Insomnia	‘There is insufficient evidence to support the use of herbal medicine [including valerian] for insomnia’ (Leach and Page, 2015)
10	Bioflavonoid complex	24.6	24.4	d	Hesperidin, rutin, naringin, quercitin and others.	To support optimal health	e
11	Green coffeef Coffea Arabica	23.4	40.7	Seeds	Caffeine, chlorogenic acids, diterpenes, lipids	Weight loss	‘the results …..are promising, but the studies are all of poor methodological quality’ (Onakpoya et al., 2011b)
12	Yohimbe Pausinystalia johimbe	21.8	9.1	Bark	Indole alkaloids (e.g. yohimbine)	body weight reduction, erectile dysfunction	No recent systematic review/meta‐analyses published
13	Ivy Hedera helix	18.6	129.4	Leaf	Sterols, saponins, flavonoids, alkaloids	Respiratory diseases	‘Although all studies report that ivy extracts are effective to reduce symptoms of upper respiratory tract infections, there is no convincing evidence due to serious methodological flaws and lack of placebo controls’ (Holzinger and Chenot, 2011)
14	Aloe vera (Aloe gel) Aloe vera	17.1	1.5	Mucilaginous tissue from the leaves	Polysaccharides, aloins	Dermatological conditions	Phlebitis ‘There is no strong evidence for preventing or treating infusion phlebitis with external application of Aloe vera.’ (Zheng et al., 2014) Acute and chronic wounds ‘There is currently an absence of high quality clinical trial evidence to support the use of Aloe vera topical agents or Aloe vera dressings as treatments for acute and chronic wounds’ (Dat et al., 2012). Psoriasis ‘Results on the effectiveness of Aloe vera are contradictory; our analysis reveals the presence of methodological gaps preventing to reach final conclusions’ (Miroddi et al., 2015)
15	Saw palmetto Serenoa repens	16.8	−6.4	Fruits	Fatty acids, sterols	Benign prostatic hyperplasia	‘Serenoa repens, at double and triple doses, did not improve urinary flow measures or prostate size in men with lower urinary tract symptoms consistent with benign prostatic hyperplasia’ (Tacklind et al., 2012)
16	Milk thistle Silybum marianum	16.8	2.6	Fruits	A mixture of flavonolignans called silymarin	Liver diseases	‘The clinical evidence of therapeutic effect of silymarin in toxic liver diseases is scarce... It is reasonable to employ silymarin as a supportive element in the therapy of Amanita phalloides poisoning but also (alcoholic and grade Child ‘A’) liver cirrhosis’ (Saller et al., 2008).
17	Garlic Allium sativum	16.5	8.4	Bulb	Alliin, diallyl disulphide, ajoens	Hypercholesterolemia, Hypertension	Hypercholesterolemia ‘Garlic reduces total cholesterol to a modest extent,without appreciable LDL lowering or HDL elevation’ (Reinhart et al., 2009).   Hypertension: ‘Although evidence from this review suggests that garlic preparations may lower blood pressure in hypertensive individuals, the evidence is not strong’ (Rohner et al., 2015).
18	Plant sterols	16.2	46.5	NA	NA	Hypercholesterolemia, hypertriglyceridemia	‘Results show that phytosterols exert a modest triclycerides‐lowering effect which is dependent on baseline concentrations’ (Demonty et al., 2013).
19	Turmeric Curcuma longa	15.7	117.7	Rhizome	Curcuminoids	Inflammatory/autoimmune diseases Dermatological conditions	Arthritis ‘These RCTs provide scientific evidence that supports the efficacy of turmeric extract in the treatment of arthritis. However, the total number of RCTs included in the analysis, the total sample size, and the methodological quality of the primary studies were not sufficient to draw definitive conclusions’ (Daily et al., 2016)   Dermatological conditions (acne, alopecia, atopic dermatitis, facial photoaging, oral lichen planus, pruritus, psoriasis, radiodermatitis, and vitiligo: ‘There is early evidence that turmeric/curcumin products and supplements, both oral and topical, may provide therapeutic benefits for skin health. However, currently published studies are limited’ (Vaughn et al., 2016)
20	Cinnamon Cinnamomum spp	14.6	2.2	Bark	Volatile oil, the main component is cinnamaldehyde	Loss of appetite, dyspepsia, diabetes	No recent systematic reviews/meta‐analyses available

^aMillion US dollars in rounded figures (Sales are from Smith et al., 2016);

^bbased on systematic reviews/meta‐analyses of clinical data;

^cherb coded as a primary substance in throat lozenges that may contain other herbs;

^dBioflavonoids are extracted from Citrus fruits;

^eCitrus flavonoids are mainly promoted as antioxidants to promote and support optimal health. Many systematic reviews are available related to flavonoid intake and a number of conditions such as oxidative stress, immune functions, cancer prevention and decline of cognitive functions

^ffrom not‐roasted coffee beans;

NA = not applicable.