The hydrogen isotopic compositions of the leaf-wax n-alkanes (δDalk) and n-alkanoic acids (δDacid) are known to reflect ambient climatic conditions (including precipitation δD values, δDPrecip). However, the climatic conditions of exactly which period (i.e. early or entire period of the leaf’s lifespan) these biomarkers represent, i.e. the seasonality in δDalk and δDacid records, is still evolving. The seasonality studies on the δDalk and δDacid values, done only in extra-tropical regions, mostly indicate the δDalk values are biased towards the early growing season whereas δDacid values are not biased towards any season. To decipher the seasonality in the δDalk and δDacid records from the tropics, we conducted a long-duration experiment wherein deciduous and evergreen species were grown using normal water (δD = −2‰) during the early stages of the leaf's growth and later using isotopically-labeled water (δD = 1000‰). Our experiment revealed (i) in deciduous and evergreen species, δDalk and δDacid values reflect δDPrecip during the early stages of the leaf's growth, (ii) synchronous synthesis of n-alkanes and n-alkanoic acids, and (iii) in deciduous species, minor incorporation of the previous year’s photosynthates in the leaf wax pool of the current year’s mature leaves. Our study suggests that the δDalk and δDacid records in the tropics are biased towards the climatic conditions prevailing during the early stages of the leaf's growth. This bias should be considered while comparing the δDPrecip values generated from the leaf wax proxy records and isotope-enabled atmospheric circulation models.