Results: Women with high caffeine intakes had significantly higher rates of bone loss at the spine than did those with low intakes (−1.90 ± 0.97% compared with 1.19 ± 1.08%; P = 0.038). When the data were analyzed according to VDR genotype and caffeine intake, women with the tt genotype had significantly (P = 0.054) higher rates of bone loss at the spine (−8.14 ± 2.62%) than did women with the TT genotype (−0.34 ± 1.42%) when their caffeine intake was >300 mg/d…In 1994, Morrison et al (22) first reported an association between vitamin D receptor gene (VDR) polymorphism and BMD of the spine and hip in adults. After this initial report, the relation between VDR polymorphism and BMD, bone turnover, and bone loss has been extensively evaluated. The results of some studies support an association between VDR polymorphism and BMD (23-,25), whereas other studies showed no evidence for this association (26,27)…At baseline, no significant differences existed in serum parathyroid hormone, serum 25-hydroxyvitamin D, serum osteocalcin, and urinary N-telopeptide between the low- and high-caffeine groups (Table 1⇑). In the longitudinal study, the percentage of change in serum parathyroid hormone concentrations was significantly lower in the high-caffeine group than in the low-caffeine group (Table 2⇑). However, no significant differences existed in the percentage of change in serum 25-hydroxyvitamin D

Alex recalled one week during his junior year when he had four term papers due. Minutes after waking on Monday, around 7.30am, he swallowed some "immediate-release" Adderall. The drug, along with a steady stream of caffeine, helped him to concentrate during classes and meetings, but he noticed some odd effects; at a morning tutorial, he explained to me in an email, "I alternated between speaking too quickly and thoroughly on some subjects and feeling awkwardly quiet during other points of the discussion." Lunch was a blur: "It's always hard to eat much when on Adderall." That afternoon he went to the library, where he spent "too much time researching a paper rather than actually writing it - a problem that is common to all intellectually curious students on stimulants". At eight he attended a two-hour meeting "with a group focused on student mental health issues". Alex then "took an extended-release Adderall" and worked productively on the paper all night. At eight the next morning he attended a meeting of his student organisation; he felt like "a zombie" and went back to his room. He fell asleep until noon, waking "in time to polish my first paper and hand it in".

Be patient.  Even though you may notice some improvements right away (sometimes within the first day), you should give your brain supplement at least several months to work.  The positive effects are cumulative, and most people do not max out their brain potential on a supplement until they have used it for at least 90 days.  That is when the really dramatic effects start kicking in!
Nootropics (/noʊ.əˈtrɒpɪks/ noh-ə-TROP-iks) (colloquial: smart drugs and cognitive enhancers) are drugs, supplements, and other substances that may improve cognitive function, particularly executive functions, memory, creativity, or motivation, in healthy individuals.[1] While many substances are purported to improve cognition, research is at a preliminary stage as of 2018, and the effects of the majority of these agents are not fully determined.