Babe Ruth has smashed the most career home runs by a player younger than 38, with 652 home runs.

Interpreted as:

most homerun before turning 38 years old by a player

	NAME	HR	G	AB	R	H	2B	3B	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Babe Ruth B. Ruth	652	2,214	7,504	1,985	2,617	468	129	2,013	1,823	40	1,154	118		9,483	5,299	1,249	116				.349	.478	.706	1.184
2	Alex Rodriguez A. Rodriguez	647	2,524	9,662	1,898	2,901	512	30	1,950	1,217	167	2,032	318	74	11,163	5,414	1,189	16	101	91	235	.300	.384	.560	.945
3	Hank Aaron H. Aaron	639	2,715	10,447	1,902	3,272	562	95	1,960	1,098	29	1,157	234	70	11,698	5,941	1,296	19	105	255	277	.313	.377	.569	.945
4	Albert Pujols A. Pujols	614	2,575	9,731	1,723	2,968	619	16	1,918	1,251	102	1,146	110	41	11,188	5,461	1,249	1	103	307	362	.305	.386	.561	.947
5	Barry Bonds B. Bonds	595	2,386	8,186	1,785	2,400	502	73	1,604	1,841	71	1,314	489	139	10,182	4,833	1,170	4	80	396	129	.293	.424	.590	1.014
6	Ken Griffey Jr. K. Griffey Jr.	593	2,378	8,826	1,545	2,558	473	37	1,701	1,162	77	1,593	184	68	10,167	4,884	1,103	8	94	230	177	.290	.374	.553	.927
7	Willie Mays W. Mays	590	2,469	9,220	1,775	2,844	450	129	1,662	1,149	33	1,159	301	94	10,485	5,322	1,169	7	76	169	214	.308	.384	.577	.961
8	Sammy Sosa S. Sosa	588	2,240	8,401	1,422	2,304	355	44	1,575	895	56	2,194	234	107	9,442	4,511	987	17	73	151	191	.274	.345	.537	.882
9	Mark McGwire M. McGwire	582	1,869	6,171	1,166	1,623	252	6	1,409	1,316	74	1,589	12	8	7,642	3,633	840	3	78	150	147	.263	.394	.589	.983
10	Harmon Killebrew H. Killebrew	552	2,263	7,664	1,238	1,986	273	24	1,511	1,479	47	1,599	18	18	9,263	3,963	849	0	73	152	233	.259	.379	.517	.896
11	Manny Ramirez M. Ramirez	549	2,238	8,058	1,520	2,522	537	20	1,812	1,301	104	1,763	37	33	9,555	4,746	1,106	2	90	214	238	.313	.411	.589	1.000
12	Frank Robinson F. Robinson	546	2,549	9,226	1,705	2,750	489	69	1,683	1,278	186	1,393	198	77	10,799	5,015	1,104	15	94	199	259	.298	.391	.544	.934
13	Mickey Mantle M. Mantle	536	2,401	8,101	1,675	2,415	344	72	1,509	1,733	12	1,718	152	42	9,907	4,511	952	14	47	126	113	.298	.420	.557	.977
14	Jim Thome J. Thome	535	2,130	7,241	1,413	2,026	394	24	1,474	1,535	66	2,161	19	20	8,909	4,073	953	1	66	159	132	.280	.407	.562	.970
15	Jimmie Foxx J. Foxx	534	2,317	8,134	1,751	2,645	458	125	1,924	1,457	13	1,311	87		9,676	4,955	1,117	72			70	.325	.428	.609	1.038
16	Mike Schmidt M. Schmidt	529	2,247	7,795	1,433	2,103	380	57	1,501	1,434	73	1,820	170	90	9,417	4,184	966	16	99	186	139	.270	.384	.537	.921
17	Eddie Mathews E. Mathews	512	2,391	8,537	1,509	2,315	354	72	1,454	1,443	26	1,490	69	41	10,100	4,349	938	36	58	107	127	.271	.376	.509	.885
18	Mel Ott M. Ott	511	2,726	9,451	1,859	2,876	488	72	1,865	1,720	64	895	89		11,344	5,041	1,071	109			38	.304	.415	.533	.948
19	Lou Gehrig L. Gehrig	493	2,164	8,001	1,888	2,721	534	163	1,998	1,511	46	789	102		9,664	5,060	1,190	106			2	.340	.448	.632	1.080
20	Rafael Palmeiro R. Palmeiro	489	2,407	8,969	1,454	2,629	522	36	1,571	1,137	73	1,162	91	39	10,292	4,690	1,047	15	98	143	201	.293	.374	.523	.896
21	Miguel Cabrera M. Cabrera	488	2,464	9,177	1,459	2,869	582	17	1,732	1,162	64	1,816	39	21	10,494	4,949	1,087	5	86	235	323	.313	.390	.539	.930
22	Reggie Jackson R. Jackson	485	2,322	8,262	1,335	2,209	401	45	1,459	1,128	86	2,140	218	108	9,550	4,155	931	12	62	136	143	.267	.359	.503	.862
23	Ernie Banks E. Banks	474	2,262	8,550	1,217	2,369	380	86	1,480	695	62	1,086	49	54	9,426	4,343	940	33	86	186	209	.277	.333	.508	.841
24	Carlos Delgado C. Delgado	473	2,035	7,283	1,241	2,038	483	18	1,512	1,109	172	1,745	14	8	8,657	3,976	974	0	93	186	152	.280	.383	.546	.929
25	Adam Dunn A. Dunn	462	2,001	6,883	1,097	1,631	334	10	1,168	1,317	86	2,379	63	25	8,328	3,371	806	2	40	122	100	.237	.364	.490	.854