The modern consensus seems to be that the pure yohimbine compound is effective in some men for treating some mild types of erectile dysfunction, but does not act as an aphrodisiac.  The active ingredients in yohimbe are indole alkaloids, including yohimbine, ajmaline, yohimbiline, and pseudoyohimbine. Among these, the chemical known as yohimbine is believed to be the main active ingredient. Holmes, A., & Quirk, G. J. (2010). Pharmacological relief of anxiety eradication and the search for additional treatments for anxiety disorders – the case of yohimbine. Trends in Pharmacological Sciences, 31(1), 2–7. Online: pubmed.ncbi.nlm.nih.gov/20036429/, accessed September 3, 2019 A number of secondary reference books list “quebrachine” as a synonym for yohimbine.          Around the year 2000, Cameroon shipped P. johimbe in Europe at a rate of about 100 tons per year. Most of the bark is collected illegally by locals who are paid 150 CFA francs per kilo (about $0.10 per pound) for delivery of pre-dried bark to the side of the road. In practice, they confuse it and mix it with P.
macroceras (“false yohimbe”), a species that contains little yohimbine.  Subsequent work on yohimbine confirmed that it behaves as an aphrodisiac in animals, including rats, dogs, and golden hamsters, but did not do so in humans. According to Betz: The traditional source of yohimbine is the bark of the African tree P. johimbe. It has other uses, but the tree is sought after mainly for its bark; In practice, harvesting the bark kills the tree. The density of trees is relatively low (on average ≈ 4 usable trees/hectare). The high demand for bark-based medicines has led to overexploitation of the tree. The bark is traded in local markets and because it is rare, it is often adulterated with that of other species that contain little yohimbine.  The species is endangered.  Strictly speaking, George Barger wrote, yohimbine should have been given the scientific name quebrachin, since it was first isolated from the quebracho tree and first mentioned in the scientific literature. However, later work on P.
yohimbe was better known, so the new name stuck.  Currently, it is illegal to buy yohimbine in the UK on an OTC basis. This means that yohimbine extract from health food store can carry. The effects of yohimbine have been studied in several controlled studies on patients with different types of erectile dysfunction, but the effect has been modest. It cannot be excluded that orally administered yohimbine may have a beneficial effect in some patients with erectile dysfunction. However, due to conflicting results, it is currently not recommended in most guidelines for the treatment of erectile dysfunction.  An alkaloid is found in its bark, which has been given the name quebrachin. In 1914, two scientific papers claimed that quebrachine was chemically identical to yohimbine.  This issue was controversial, and the issue remained uncertain for a long time.  In 1972, however, Effler and Effler used modern analytical techniques such as mass spectrometry, UV absorption, IR absorption, and NMR to determine that quebrashin and yohimbine are one and the same. Yohimbe is the common English name for the tree species P. johimbe (also called Corynanthe johimbe) and in a broader sense the name of a medicinal preparation made from the bark of this tree and sold as an aphrodisiac.
 In contrast, yohimbine is a pure alkaloid that can be isolated from yohimbe bark. Cohen et al. found that brand samples sold in U.S. brick-and-mortar stores contained very different amounts of yohimbine, and sometimes not at all. : 368 Labelling claims were often misleading. : 368 Similar results have been reported by other laboratories for products sold in the United States, other countries and on the Internet.      One study found that many brands of “yohimbe” may not be derived from P. Arbre Johimbe in the first place.  According to yet another source, yohimbe sold in West African markets, where the tree grows, is frequently adulterated with other species of the genus Pausinystalia; These contain little yohimbine.  The amounts of alkaloids found even in authentic P. johimbe bark vary widely, depending on the source of the bark (roots, stem, branches, height, etc.).  Although supplements with Yohimbine HCL can be purchased in other countries via the Internet, this violates the Drug Act.
Importation is illegal and may have legal consequences. By the way: Dietary supplements advertised as “purely natural” on the internet, especially those intended for weight loss, potency enhancement or performance enhancement, often contain undeclared illegal active pharmaceutical ingredients. Be careful if such products are described as particularly effective in Internet forums. You can find the health information you can rely on on the net here. Regulation (EU) 2019/6 of the European Parliament. Official Journal of the European Union. 2019. eur-lex.europa.eu/legal-content/DE/TXT/PDF/?uri=CELEX:32019R0650&from=ES However, yohimbine is not an illegal substance to possess. So, buying yohimbine in the UK may be able to make an online purchase and have the supplement delivered to your home.
Yohimbe (Pausinystalia johimbe) is a tree that grows in West and Central Africa;  Yohimbine was originally named as extracted from yohimbe bark in 1896 by Adolph Spiegel  (but see § Aspidosperma quebracho-blanco below). In 1943, the correct constitution of Yohimbine was proposed by Witkop.  Fifteen years later, a team led by Eugene van Tamelen used a 23-step synthesis to be the first people to synthesize yohimbine.    Yohimbe, a complex mixture, has been studied much less extensively than yohimbine, the pure compound.  Pharmaceutical grade yohimbine is usually presented as hydrochloride,:3, 14,34 which is more soluble. Although well tolerated and safe, even if the likely range of therapies is largely exceeded, it is evident that the efficacy of [yohimbine] monotherapy in the general emergency department population is likely to be modest.  In the United States, yohimbe supplements are sold as dietary supplements to increase libido, lose weight, and as a bodybuilding aid; But “there is virtually no published research on Yohimbe that supports these or other claims.” :861 Often these products explicitly claim to contain yohimbine.  On the other hand, there is a “fairly rich literature on yohimbine”.  Experiments show that the alkaloid increases sexual motivation even in sexually exhausted rats due to its effect on central α2-adrenergic receptors in the locus coeruleus in the brain.